Aegisub/src/auto4_lua_assfile.cpp
2015-01-20 21:22:24 +01:00

777 lines
22 KiB
C++

// Copyright (c) 2006, Niels Martin Hansen
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Aegisub Group nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/
/// @file auto4_lua_assfile.cpp
/// @brief Lua 5.1-based scripting engine (interface to subtitle files)
/// @ingroup scripting
///
#include "auto4_lua.h"
#include "ass_dialogue.h"
#include "ass_info.h"
#include "ass_file.h"
#include "ass_karaoke.h"
#include "ass_style.h"
#include "compat.h"
#include <libaegisub/exception.h>
#include <libaegisub/log.h>
#include <libaegisub/lua/utils.h>
#include <libaegisub/make_unique.h>
#include <algorithm>
#include <boost/algorithm/string/case_conv.hpp>
#include <cassert>
#include <memory>
namespace {
using namespace agi::lua;
DEFINE_EXCEPTION(BadField, Automation4::MacroRunError);
BadField bad_field(const char *expected_type, const char *name, const char *line_clasee)
{
return BadField(std::string("Invalid or missing field '") + name + "' in '" + line_clasee + "' class subtitle line (expected " + expected_type + ")");
}
std::string get_string_field(lua_State *L, const char *name, const char *line_class)
{
lua_getfield(L, -1, name);
if (!lua_isstring(L, -1))
throw bad_field("string", name, line_class);
std::string ret(lua_tostring(L, -1));
lua_pop(L, 1);
return ret;
}
double get_double_field(lua_State *L, const char *name, const char *line_class)
{
lua_getfield(L, -1, name);
if (!lua_isnumber(L, -1))
throw bad_field("number", name, line_class);
double ret = lua_tonumber(L, -1);
lua_pop(L, 1);
return ret;
}
int get_int_field(lua_State *L, const char *name, const char *line_class)
{
lua_getfield(L, -1, name);
if (!lua_isnumber(L, -1))
throw bad_field("number", name, line_class);
int ret = lua_tointeger(L, -1);
lua_pop(L, 1);
return ret;
}
bool get_bool_field(lua_State *L, const char *name, const char *line_class)
{
lua_getfield(L, -1, name);
if (!lua_isboolean(L, -1))
throw bad_field("boolean", name, line_class);
bool ret = !!lua_toboolean(L, -1);
lua_pop(L, 1);
return ret;
}
using namespace Automation4;
template<int (LuaAssFile::*closure)(lua_State *)>
int closure_wrapper(lua_State *L)
{
return (LuaAssFile::GetObjPointer(L, lua_upvalueindex(1), false)->*closure)(L);
}
template<void (LuaAssFile::*closure)(lua_State *), bool allow_expired>
int closure_wrapper_v(lua_State *L)
{
(LuaAssFile::GetObjPointer(L, lua_upvalueindex(1), allow_expired)->*closure)(L);
return 0;
}
int modification_mask(AssEntry *e)
{
if (!e) return AssFile::COMMIT_SCRIPTINFO;
switch (e->Group()) {
case AssEntryGroup::DIALOGUE: return AssFile::COMMIT_DIAG_ADDREM;
case AssEntryGroup::STYLE: return AssFile::COMMIT_STYLES;
default: return AssFile::COMMIT_SCRIPTINFO;
}
}
template<typename T, typename U>
const T *check_cast_constptr(const U *value) {
return typeid(const T) == typeid(*value) ? static_cast<const T *>(value) : nullptr;
}
}
namespace Automation4 {
LuaAssFile::~LuaAssFile() { }
void LuaAssFile::CheckAllowModify()
{
if (!can_modify)
error(L, "Attempt to modify subtitles in read-only feature context.");
}
void LuaAssFile::CheckBounds(int idx)
{
if (idx <= 0 || idx > (int)lines.size())
error(L, "Requested out-of-range line from subtitle file: %d", idx);
}
void LuaAssFile::AssEntryToLua(lua_State *L, size_t idx)
{
lua_newtable(L);
const AssEntry *e = lines[idx];
if (!e)
e = &ass->Info[idx];
set_field(L, "section", e->GroupHeader());
if (auto info = check_cast_constptr<AssInfo>(e)) {
set_field(L, "raw", info->GetEntryData());
set_field(L, "key", info->Key());
set_field(L, "value", info->Value());
set_field(L, "class", "info");
}
else if (auto dia = check_cast_constptr<AssDialogue>(e)) {
set_field(L, "raw", dia->GetEntryData());
set_field(L, "comment", dia->Comment);
set_field(L, "layer", dia->Layer);
set_field(L, "start_time", dia->Start);
set_field(L, "end_time", dia->End);
set_field(L, "style", dia->Style);
set_field(L, "actor", dia->Actor);
set_field(L, "effect", dia->Effect);
set_field(L, "margin_l", dia->Margin[0]);
set_field(L, "margin_r", dia->Margin[1]);
set_field(L, "margin_t", dia->Margin[2]);
set_field(L, "margin_b", dia->Margin[2]);
set_field(L, "text", dia->Text);
// create extradata table
lua_newtable(L);
for (auto const& ed : ass->GetExtradata(dia->ExtradataIds)) {
push_value(L, ed.key);
push_value(L, ed.value);
lua_settable(L, -3);
}
lua_setfield(L, -2, "extra");
set_field(L, "class", "dialogue");
}
else if (auto sty = check_cast_constptr<AssStyle>(e)) {
set_field(L, "raw", sty->GetEntryData());
set_field(L, "name", sty->name);
set_field(L, "fontname", sty->font);
set_field(L, "fontsize", sty->fontsize);
set_field(L, "color1", sty->primary.GetAssStyleFormatted() + "&");
set_field(L, "color2", sty->secondary.GetAssStyleFormatted() + "&");
set_field(L, "color3", sty->outline.GetAssStyleFormatted() + "&");
set_field(L, "color4", sty->shadow.GetAssStyleFormatted() + "&");
set_field(L, "bold", sty->bold);
set_field(L, "italic", sty->italic);
set_field(L, "underline", sty->underline);
set_field(L, "strikeout", sty->strikeout);
set_field(L, "scale_x", sty->scalex);
set_field(L, "scale_y", sty->scaley);
set_field(L, "spacing", sty->spacing);
set_field(L, "angle", sty->angle);
set_field(L, "borderstyle", sty->borderstyle);
set_field(L, "outline", sty->outline_w);
set_field(L, "shadow", sty->shadow_w);
set_field(L, "align", sty->alignment);
set_field(L, "margin_l", sty->Margin[0]);
set_field(L, "margin_r", sty->Margin[1]);
set_field(L, "margin_t", sty->Margin[2]);
set_field(L, "margin_b", sty->Margin[2]);
set_field(L, "encoding", sty->encoding);
set_field(L, "relative_to", 2);// From STS.h: "0: window, 1: video, 2: undefined (~window)"
set_field(L, "class", "style");
}
else {
assert(false);
}
}
std::unique_ptr<AssEntry> LuaAssFile::LuaToAssEntry(lua_State *L, AssFile *ass)
{
// assume an assentry table is on the top of the stack
// convert it to a real AssEntry object, and pop the table from the stack
if (!lua_istable(L, -1))
error(L, "Can't convert a non-table value to AssEntry");
lua_getfield(L, -1, "class");
if (!lua_isstring(L, -1))
error(L, "Table lacks 'class' field, can't convert to AssEntry");
std::string lclass(lua_tostring(L, -1));
boost::to_lower(lclass);
lua_pop(L, 1);
std::unique_ptr<AssEntry> result;
if (lclass == "info")
result = agi::make_unique<AssInfo>(get_string_field(L, "key", "info"), get_string_field(L, "value", "info"));
else if (lclass == "style") {
auto sty = new AssStyle;
result.reset(sty);
sty->name = get_string_field(L, "name", "style");
sty->font = get_string_field(L, "fontname", "style");
sty->fontsize = get_double_field(L, "fontsize", "style");
sty->primary = get_string_field(L, "color1", "style");
sty->secondary = get_string_field(L, "color2", "style");
sty->outline = get_string_field(L, "color3", "style");
sty->shadow = get_string_field(L, "color4", "style");
sty->bold = get_bool_field(L, "bold", "style");
sty->italic = get_bool_field(L, "italic", "style");
sty->underline = get_bool_field(L, "underline", "style");
sty->strikeout = get_bool_field(L, "strikeout", "style");
sty->scalex = get_double_field(L, "scale_x", "style");
sty->scaley = get_double_field(L, "scale_y", "style");
sty->spacing = get_double_field(L, "spacing", "style");
sty->angle = get_double_field(L, "angle", "style");
sty->borderstyle = get_int_field(L, "borderstyle", "style");
sty->outline_w = get_double_field(L, "outline", "style");
sty->shadow_w = get_double_field(L, "shadow", "style");
sty->alignment = get_int_field(L, "align", "style");
sty->Margin[0] = get_int_field(L, "margin_l", "style");
sty->Margin[1] = get_int_field(L, "margin_r", "style");
sty->Margin[2] = get_int_field(L, "margin_t", "style");
sty->encoding = get_int_field(L, "encoding", "style");
sty->UpdateData();
}
else if (lclass == "dialogue") {
assert(ass != 0); // since we need AssFile::AddExtradata
auto dia = new AssDialogue;
result.reset(dia);
dia->Comment = get_bool_field(L, "comment", "dialogue");
dia->Layer = get_int_field(L, "layer", "dialogue");
dia->Start = get_int_field(L, "start_time", "dialogue");
dia->End = get_int_field(L, "end_time", "dialogue");
dia->Style = get_string_field(L, "style", "dialogue");
dia->Actor = get_string_field(L, "actor", "dialogue");
dia->Margin[0] = get_int_field(L, "margin_l", "dialogue");
dia->Margin[1] = get_int_field(L, "margin_r", "dialogue");
dia->Margin[2] = get_int_field(L, "margin_t", "dialogue");
dia->Effect = get_string_field(L, "effect", "dialogue");
dia->Text = get_string_field(L, "text", "dialogue");
std::vector<uint32_t> new_ids;
lua_getfield(L, -1, "extra");
auto type = lua_type(L, -1);
if (type == LUA_TTABLE) {
lua_for_each(L, [&] {
if (lua_type(L, -2) != LUA_TSTRING) return;
new_ids.push_back(ass->AddExtradata(
get_string_or_default(L, -2),
get_string_or_default(L, -1)));
});
std::sort(begin(new_ids), end(new_ids));
dia->ExtradataIds = std::move(new_ids);
}
else if (type != LUA_TNIL) {
error(L, "dialogue extradata must be a table");
}
}
else {
error(L, "Found line with unknown class: %s", lclass.c_str());
return nullptr;
}
return result;
}
int LuaAssFile::ObjectIndexRead(lua_State *L)
{
switch (lua_type(L, 2)) {
case LUA_TNUMBER:
{
// read an indexed AssEntry
int idx = lua_tointeger(L, 2);
CheckBounds(idx);
AssEntryToLua(L, idx - 1);
return 1;
}
case LUA_TSTRING:
{
// either return n or a function doing further stuff
const char *idx = lua_tostring(L, 2);
if (strcmp(idx, "n") == 0) {
// get number of items
lua_pushnumber(L, lines.size());
return 1;
}
lua_pushvalue(L, 1);
if (strcmp(idx, "delete") == 0)
lua_pushcclosure(L, closure_wrapper_v<&LuaAssFile::ObjectDelete, false>, 1);
else if (strcmp(idx, "deleterange") == 0)
lua_pushcclosure(L, closure_wrapper_v<&LuaAssFile::ObjectDeleteRange, false>, 1);
else if (strcmp(idx, "insert") == 0)
lua_pushcclosure(L, closure_wrapper_v<&LuaAssFile::ObjectInsert, false>, 1);
else if (strcmp(idx, "append") == 0)
lua_pushcclosure(L, closure_wrapper_v<&LuaAssFile::ObjectAppend, false>, 1);
else if (strcmp(idx, "script_resolution") == 0)
lua_pushcclosure(L, closure_wrapper<&LuaAssFile::LuaGetScriptResolution>, 1);
else {
// idiot
lua_pop(L, 1);
return error(L, "Invalid indexing in Subtitle File object: '%s'", idx);
}
return 1;
}
default:
// crap, user is stupid!
return error(L, "Attempt to index a Subtitle File object with value of type '%s'.", lua_typename(L, lua_type(L, 2)));
}
assert(false);
return 0;
}
void LuaAssFile::InitScriptInfoIfNeeded()
{
if (script_info_copied) return;
size_t i = 0;
for (auto const& info : ass->Info) {
// Just in case an insane user inserted non-info lines into the
// script info section...
while (lines[i]) ++i;
lines_to_delete.emplace_back(agi::make_unique<AssInfo>(info));
lines[i++] = lines_to_delete.back().get();
}
script_info_copied = true;
}
void LuaAssFile::QueueLineForDeletion(size_t idx)
{
if (!lines[idx] || lines[idx]->Group() == AssEntryGroup::INFO)
InitScriptInfoIfNeeded();
else
lines_to_delete.emplace_back(lines[idx]);
}
void LuaAssFile::AssignLine(size_t idx, std::unique_ptr<AssEntry> e)
{
auto group = e->Group();
if (group == AssEntryGroup::INFO)
InitScriptInfoIfNeeded();
lines[idx] = e.get();
if (group == AssEntryGroup::INFO)
lines_to_delete.emplace_back(std::move(e));
else
e.release();
}
void LuaAssFile::InsertLine(std::vector<AssEntry *> &vec, size_t idx, std::unique_ptr<AssEntry> e)
{
auto group = e->Group();
if (group == AssEntryGroup::INFO)
InitScriptInfoIfNeeded();
vec.insert(vec.begin() + idx, e.get());
if (group == AssEntryGroup::INFO)
lines_to_delete.emplace_back(std::move(e));
else
e.release();
}
void LuaAssFile::ObjectIndexWrite(lua_State *L)
{
// instead of implementing everything twice, just call the other modification-functions from here
// after modifying the stack to match their expectations
CheckAllowModify();
int n = check_int(L, 2);
if (n < 0) {
// insert line so new index is n
lua_remove(L, 1);
lua_pushinteger(L, -n);
lua_replace(L, 1);
ObjectInsert(L);
}
else if (n == 0) {
// append line to list
lua_remove(L, 1);
lua_remove(L, 1);
ObjectAppend(L);
}
else {
// replace line at index n or delete
if (!lua_isnil(L, 3)) {
// insert
CheckBounds(n);
auto e = LuaToAssEntry(L, ass);
modification_type |= modification_mask(e.get());
QueueLineForDeletion(n - 1);
AssignLine(n - 1, std::move(e));
}
else {
// delete
lua_remove(L, 1);
lua_remove(L, 1);
ObjectDelete(L);
}
}
}
int LuaAssFile::ObjectGetLen(lua_State *L)
{
lua_pushnumber(L, lines.size());
return 1;
}
void LuaAssFile::ObjectDelete(lua_State *L)
{
CheckAllowModify();
// get number of items to delete
int itemcount = lua_gettop(L);
if (itemcount == 0) return;
std::vector<size_t> ids;
if (itemcount == 1 && lua_istable(L, 1)) {
lua_pushvalue(L, 1);
lua_for_each(L, [&] {
size_t n = check_uint(L, -1);
argcheck(L, n > 0 && n <= lines.size(), 1, "Out of range line index");
ids.push_back(n - 1);
});
}
else {
ids.reserve(itemcount);
while (itemcount > 0) {
size_t n = check_uint(L, -1);
argcheck(L, n > 0 && n <= lines.size(), itemcount, "Out of range line index");
ids.push_back(n - 1);
--itemcount;
}
}
sort(ids.begin(), ids.end());
size_t id_idx = 0, out = 0;
for (size_t i = 0; i < lines.size(); ++i) {
if (id_idx < ids.size() && ids[id_idx] == i) {
modification_type |= modification_mask(lines[i]);
QueueLineForDeletion(i);
++id_idx;
}
else {
lines[out++] = lines[i];
}
}
lines.erase(lines.begin() + out, lines.end());
}
void LuaAssFile::ObjectDeleteRange(lua_State *L)
{
CheckAllowModify();
size_t a = std::max<size_t>(check_uint(L, 1), 1) - 1;
size_t b = std::min<size_t>(check_uint(L, 2), lines.size());
if (a >= b) return;
for (size_t i = a; i < b; ++i) {
modification_type |= modification_mask(lines[i]);
QueueLineForDeletion(i);
}
lines.erase(lines.begin() + a, lines.begin() + b);
}
void LuaAssFile::ObjectAppend(lua_State *L)
{
CheckAllowModify();
int n = lua_gettop(L);
for (int i = 1; i <= n; i++) {
lua_pushvalue(L, i);
auto e = LuaToAssEntry(L, ass);
modification_type |= modification_mask(e.get());
if (lines.empty()) {
InsertLine(lines, 0, std::move(e));
continue;
}
// Find the appropriate place to put it
auto group = e->Group();
for (size_t i = lines.size(); i > 0; --i) {
auto cur_group = lines[i - 1] ? lines[i - 1]->Group() : AssEntryGroup::INFO;
if (cur_group == group) {
InsertLine(lines, i, std::move(e));
break;
}
}
// No lines of this type exist already, so just append it to the end
if (e) InsertLine(lines, lines.size(), std::move(e));
}
}
void LuaAssFile::ObjectInsert(lua_State *L)
{
CheckAllowModify();
size_t before = check_uint(L, 1);
// + 1 to allow appending at the end of the file
argcheck(L, before > 0 && before <= lines.size() + 1, 1,
"Out of range line index");
if (before == lines.size() + 1) {
lua_remove(L, 1);
ObjectAppend(L);
return;
}
int n = lua_gettop(L);
std::vector<AssEntry *> new_entries;
new_entries.reserve(n - 1);
for (int i = 2; i <= n; i++) {
lua_pushvalue(L, i);
auto e = LuaToAssEntry(L, ass);
modification_type |= modification_mask(e.get());
InsertLine(new_entries, i - 2, std::move(e));
lua_pop(L, 1);
}
lines.insert(lines.begin() + before - 1, new_entries.begin(), new_entries.end());
}
void LuaAssFile::ObjectGarbageCollect(lua_State *L)
{
references--;
if (!references) delete this;
LOG_D("automation/lua") << "Garbage collected LuaAssFile";
}
int LuaAssFile::ObjectIPairs(lua_State *L)
{
lua_pushvalue(L, lua_upvalueindex(1)); // push 'this' as userdata
lua_pushcclosure(L, closure_wrapper<&LuaAssFile::IterNext>, 1);
lua_pushnil(L);
push_value(L, 0);
return 3;
}
int LuaAssFile::IterNext(lua_State *L)
{
size_t i = check_uint(L, 2);
if (i >= lines.size()) {
lua_pushnil(L);
return 1;
}
push_value(L, i + 1);
AssEntryToLua(L, i);
return 2;
}
int LuaAssFile::LuaParseKaraokeData(lua_State *L)
{
auto e = LuaToAssEntry(L, ass);
auto dia = check_cast_constptr<AssDialogue>(e.get());
argcheck(L, !!dia, 1, "Subtitle line must be a dialogue line");
int idx = 0;
// 2.1.x stored everything before the first syllable at index zero
// There's no longer any such thing with the new parser, but scripts
// may rely on kara[0] existing so add an empty syllable
lua_createtable(L, 0, 6);
set_field(L, "duration", 0);
set_field(L, "start_time", 0);
set_field(L, "end_time", 0);
set_field(L, "tag", "");
set_field(L, "text", "");
set_field(L, "text_stripped", "");
lua_rawseti(L, -2, idx++);
AssKaraoke kara(dia, false, false);
for (auto const& syl : kara) {
lua_createtable(L, 0, 6);
set_field(L, "duration", syl.duration);
set_field(L, "start_time", syl.start_time - dia->Start);
set_field(L, "end_time", syl.start_time + syl.duration - dia->Start);
set_field(L, "tag", syl.tag_type);
set_field(L, "text", syl.GetText(false));
set_field(L, "text_stripped", syl.text);
lua_rawseti(L, -2, idx++);
}
return 1;
}
int LuaAssFile::LuaGetScriptResolution(lua_State *L)
{
int w, h;
ass->GetResolution(w, h);
push_value(L, w);
push_value(L, h);
return 2;
}
void LuaAssFile::LuaSetUndoPoint(lua_State *L)
{
if (!can_set_undo)
error(L, "Attempt to set an undo point in a context where it makes no sense to do so.");
if (modification_type) {
pending_commits.emplace_back();
PendingCommit& back = pending_commits.back();
back.modification_type = modification_type;
back.mesage = to_wx(check_string(L, 1));
back.lines = lines;
modification_type = 0;
}
}
LuaAssFile *LuaAssFile::GetObjPointer(lua_State *L, int idx, bool allow_expired)
{
assert(lua_type(L, idx) == LUA_TUSERDATA);
auto ud = lua_touserdata(L, idx);
auto laf = *static_cast<LuaAssFile **>(ud);
if (!allow_expired && laf->references < 2)
error(L, "Subtitles object is no longer valid");
return laf;
}
std::vector<AssEntry *> LuaAssFile::ProcessingComplete(wxString const& undo_description)
{
auto apply_lines = [&](std::vector<AssEntry *> const& lines) {
if (script_info_copied)
ass->Info.clear();
ass->Styles.clear();
ass->Events.clear();
for (auto line : lines) {
if (!line) continue;
switch (line->Group()) {
case AssEntryGroup::INFO: ass->Info.push_back(*static_cast<AssInfo *>(line)); break;
case AssEntryGroup::STYLE: ass->Styles.push_back(*static_cast<AssStyle *>(line)); break;
case AssEntryGroup::DIALOGUE: ass->Events.push_back(*static_cast<AssDialogue *>(line)); break;
default: break;
}
}
};
// Apply any pending commits
for (auto const& pc : pending_commits) {
apply_lines(pc.lines);
ass->Commit(pc.mesage, pc.modification_type);
}
// Commit any changes after the last undo point was set
if (modification_type)
apply_lines(lines);
if (modification_type && can_set_undo && !undo_description.empty())
ass->Commit(undo_description, modification_type);
lines_to_delete.clear();
auto ret = std::move(lines);
references--;
if (!references) delete this;
return ret;
}
void LuaAssFile::Cancel()
{
for (auto& line : lines_to_delete) line.release();
references--;
if (!references) delete this;
}
LuaAssFile::LuaAssFile(lua_State *L, AssFile *ass, bool can_modify, bool can_set_undo)
: ass(ass)
, L(L)
, can_modify(can_modify)
, can_set_undo(can_set_undo)
{
for (auto& line : ass->Info)
lines.push_back(nullptr);
for (auto& line : ass->Styles)
lines.push_back(&line);
for (auto& line : ass->Events)
lines.push_back(&line);
// prepare userdata object
*static_cast<LuaAssFile**>(lua_newuserdata(L, sizeof(LuaAssFile*))) = this;
// make the metatable
lua_createtable(L, 0, 5);
set_field<closure_wrapper<&LuaAssFile::ObjectIndexRead>>(L, "__index");
set_field<closure_wrapper_v<&LuaAssFile::ObjectIndexWrite, false>>(L, "__newindex");
set_field<closure_wrapper<&LuaAssFile::ObjectGetLen>>(L, "__len");
set_field<closure_wrapper_v<&LuaAssFile::ObjectGarbageCollect, true>>(L, "__gc");
set_field<closure_wrapper<&LuaAssFile::ObjectIPairs>>(L, "__ipairs");
lua_setmetatable(L, -2);
// register misc functions
// assume the "aegisub" global table exists
lua_getglobal(L, "aegisub");
set_field<closure_wrapper<&LuaAssFile::LuaParseKaraokeData>>(L, "parse_karaoke_data");
set_field<closure_wrapper_v<&LuaAssFile::LuaSetUndoPoint, false>>(L, "set_undo_point");
lua_pop(L, 1); // pop "aegisub" table
// Leaves userdata object on stack
}
}